Optical sensors for weapons, must be able to observe the flight path and targets while operating in extreme flight environments. Typically, the weapons are constructed with a window that protects the sensors, while allowing the sensors to detect infrared (IR). As a weapon is travelling through air, heat is generated at the window. This heat creates an IR signature that "masks off" incoming IR information. It is therefor necessary that the window be cooled.
One method of cooling the window includes blowing a coolant across the face of the window. To insure that the window temperature is brought within working limits, a large cooling system is required to provide the velocity and quantity of coolant to cool the window. This system is large and heavy, reducing the overall effectiveness of the weapon.
Another cooling concept is to have a mosaic window, wherein transparent blocks are attached to a metal grid. The metal grid provides structural support for the blocks. Between the metal and the blocks are slots that allow coolant to flow through and cool the window. The resultant window provides a more efficient cooling system. Although the window is cooled, the sensor must look through the metal grid, which will reflect any incoming IR. Additionally, there are requirements that the window have a contoured surface. One process for creating such a window, is to attach the mosaic blocks and then grind the blocks and metal to the desired shape. During the grinding step, the metal tends to "smear" or deform into the slots, preventing or restricting the coolant from flowing through the slots. Thus what is needed is an efficiently cooled window that is capable of being formed into contour shapes.